In patent publication 1 and patent publication 2 described below, there is disclosed a submount for an LED-array as a light emitting element. An outline of this structure will be described using FIG. 1 and FIG. 2.
The submount 100 of this related art comprises a submount substrate 101, a wiring electrode 102, and a light emitting element electrode 103. The wiring electrode 102, as shown in FIG. 1, is formed across a surface (the right side surface in FIG. 1) and a side surface (upper surface in FIG. 1) of the submount substrate 101. Also, as shown in FIG. 2, a light emitting element 104 is mounted on the electrode 103.
An example of an optical module using this type of submount 100 is shown in FIG. 2. With this example, the submount 100 is mounted on a module substrate 200. An IC 300 is also mounted on the module substrate 200. The IC 300 is for driving a light emitting element 104 causing it to emit light.
With the example of FIG. 2, the optical axis of light emitted from the light emitting element 104 is arranged parallel to the surface of the substrate 200. By doing this, it is possible to arrange an optical fiber for receiving light in parallel on the substrate 200, which makes it possible to miniaturize the overall optical module including the optical fiber (refer to patent publication 3 below).
With this related art optical module, a connection is made between the IC 300 and a wiring electrode 102 using a bonding wire 400. Also, a connection is made between the wiring electrode 102 and the light emitting element 104 using a bonding wire 500.
In this way, with this related art technology it is possible to electrically connect a drive IC 300 and a light emitting element 104.
Also, with this related art technology, since a wiring electrode 102 is formed on a side surface of a submount substrate 101, it is possible to connect a bonding wire 400 to the wiring electrode 102. The bonding wire 500 for connecting the wiring electrode 102 and the light emitting element 104 is wired before attaching the submount substrate 101 to the module substrate 200.
Incidentally, with the conventional submount 100 shown in FIG. 1 and FIG. 2, it is necessary for the wiring electrode 102 to be formed straddling a side surface and the main surface of the sub mount substrate 101. Accordingly, a bent section that is bent at about 90 degrees is formed in the wiring electrode 102. With an electrode 102 of this type of structure there is a possibility of rupture to this bend section, and there is a possibility that manufacturing process yield will become bad. Also, in order to form this type of structure a comparatively complicated processes required, and there is a problem of poor manufacturing efficiency.